The use of crop harvesting headers is known in the field of agriculture. Headers are used for a variety of purposes, such as for example to harvest crops with a header on a combine harvester or to swath crop material with a header on a swather.
Harvesting equipment may be equipped with a header located generally at its front portion. The header may be generally oriented transverse to the direction of movement of the harvesting equipment during operation. The header may include a support frame, a cutting system (often referred to as a “cutter bar”) to cut the portion of the crop that is to be harvested, a crop collection system having a surface or “table” onto which cut crop material can be collected and transported for further processing, and a rotating reel to collect and sweep crop material onto the collection table. A typical reel may include a main central reel tube that rotates about a reel axis and the central reel tube may be surrounded by and interconnected to a series of smaller tubes (often referred to as “bats”). Bats are typically oriented generally parallel to the main reel tube, and spaced radially apart from each other, typically with equal angular spacing about the reel axis. A plurality of structural arms (often referred as “spiders”) may extend radially from the central reel tube to support the bats in a radial position relative to the central reel tube. Each bat may be equipped with a plurality of crop collection members (which may for example be “fingers” or “tines”) and which may extend from the bats in a generally outward radial direction.
During operation of some typical headers known in the art, rotation of the main reel tube may cause the attached bats to rotate about both the central reel axis as well as about their own axis passing longitudinally along the length of the bats. Thus the fingers of the bats may also be configured to sweep standing crops towards the cutter bar as the header moves through a field, and may assist in collecting crops that have been cut by the cutter bar and moving them onto the collection surface of the crop collection system once the crop material has been cut. Fingers [tines] attached to the bats may assist in the gathering, sweeping, and collecting of crop material by creating a raking motion which may effectively engage standing crops on a field.
The performance of a header may be improved in several ways. Headers may be constructed for various requirements (such as type of crop or field conditions) by providing a means for adjusting the height or position of the reel. The motion and position of fingers [tines] may also be adjusted for improved crop engagement. For example, the angle of the fingers [tines] relative to the bats may be adjusted to optimize crop engagement. The motion of fingers [tines] may improve crop engagement, separate cut crop from uncut crop, and also facilitate release of crops from the reel onto the table.
One known mechanism for controlling the motion of bats and fingers [tines] is by a cam and cam follower system. Using a cam, bats and fingers [tines] may be guided during the rotation of the reel to follow a non-circular path. In such systems, the path of motion of bats and fingers [tines] may depend at least in part on the shape of the cam and cam follower mechanisms. However, there are disadvantages to cam-controlled bats. For example, cam-controlled bats may have increased wear and tear due to the friction between cams and cam followers. It may also be difficult to adjust cam systems because each cam design may only be optimized for a specific application, and adjustment of the reel for other requirements (such as crop type or field conditions) may require replacement of the cam system which may be quite time consuming and difficult to accomplish.
Accordingly, it may be desirable to utilize alternative ways for controlling the movement of bats and fingers [tines] on a header.